Maintaining a consistent sleep schedule may be an important factor in protecting the heart, according to new, independent, preliminary research to be presented at the American Heart Association's Scientific Sessions 2026. The meeting, set for Nov. 6–9 in Chicago, is a premier global exchange of the latest scientific advancements in heart and stroke science.
Researchers analyzed sleep data from more than 10,000 adults who wore an activity tracking device as part of the National Institutes of Health's "All of Us" Research Program, piecing together more than 1 million nights of sleep. The analysis tracked sleep quantity, quality, regularity, timing and cycles. Participants, whose average age was 53, had no heart or metabolic disease at the start of the study and were followed for a median of 3.7 years.
The findings suggest that changes in sleep timing from night to night over about a six-month period were linked to a 20% to 23% higher risk of serious heart events, including heart attack, stroke and heart failure. Each 29-minute increase in how much a person's sleep length varied from night to night was associated with a 24% higher risk of the combined cardiovascular outcome, including a 29% higher risk of cardiomyopathy and a 20% higher risk of heart failure. Having a greater number of complete sleep cycles each night was associated with a 28% lower risk of atrial arrhythmia, while an unusually long sleep cycle was linked to a 55% higher risk of heart attack or stroke.
"While we often focus on getting a full eight hours of sleep every night, having a regular sleep schedule — consistent bedtimes, wake times, and sleep duration from night to night — is a practical, actionable step anyone can take that may help protect their heart and blood vessels," said lead researcher Nguyen Minh Tuan Viet, M.D., Ph.D., a neuroscientist and postdoctoral research fellow at Boston Children's Hospital and Harvard Medical School. He noted that irregular sleep is often due to weekends or shift work. "Sometimes the quality of sleep is something we cannot control. But the regularity, consistent bedtimes throughout the week and waking up at the same time every morning, is something some people can control."
The study is an abstract presented at a scientific meeting and is not peer-reviewed; findings are considered preliminary until published in a peer-reviewed journal. Marie-Pierre St-Onge, Ph.D., a volunteer expert for the American Heart Association who chaired the Association's 2025 scientific statement, Multidimensional Sleep Health: Definitions and Implications for Cardiometabolic Health, cautioned that causality has not been established. "This study highlights another potential important sleep characteristic to consider for heart health, which adds to the body of research we currently have on sleep duration," said St-Onge, a professor at Columbia University Irving Medical Center. "However, contrary to the years of research showing how insufficient sleep affects cardiovascular risk factors, we are still lacking the data to support a causal, independent impact of sleep regularity on cardiovascular disease risk."
The research adds to a growing body of work the Association has highlighted on sleep and heart health, including releases on why body clocks matter for heart health and how sleep matters: duration, timing, quality and more may affect cardiovascular disease risk. Earlier studies have linked erratic sleep patterns to elevated blood pressure in teens with extra belly weight and found that irregular sleeping habits may increase risk of atherosclerosis in older adults. In 2022, the Association added sleep to its cardiovascular health checklist.
The study's limitations include its observational design, which cannot establish cause and effect, and the use of wearable devices at home rather than brain-monitoring equipment in a sleep lab. Still, the findings may prompt scientists to further evaluate links between sleep regularity and cardiovascular disease, so that recommendations for regularity can match those for duration. For readers, the implication is that keeping consistent bedtimes and wake times throughout the week may be a low-cost, controllable step toward better heart health, even as researchers continue to investigate the underlying mechanisms.
